Marty Itzkowitz wrote:
> Interesting problem.  I've used disk rattle as a measurement of io 
> activity before
> there were such tools for measurement.  It's crude, but effective.
> 
> To answer your question: you could try er_kernel.  It uses DTrace to
> do statistical callstack sampling, and is described on our  kernel 
> profiling page <http://dpweb.sfbay/products/analyzer/kernel.html>.
> That page is woefully out of date, but is basically correct w.r.t usage.
> We test it on Nevada and S10, and S9.
> 
> Roch Bourbonnais (PAE), who did most of the development, used it to track
> down the root cause of a similar-sounding problem in VxFS.  See the slides
> towards the end of the presentation on Kernel Profiling 
> <http://dpweb.sfbay/products/analyzer/kprof.pdf> dated June, 2002.
> 
> The best version to use on a late snv is the one from our nightly-build 
> <http://dpweb.sfbay/products/analyzer/access.html#nightly>
> 
> If you have any problems, please contact Roch and/or me;
> if you give it a try, please report your experience back to our interest
> alias,  [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> .

I looked through the page and the presentation and it wasn't clear to me
that this was going to give me information on which file was being
accessed or which process was doing the accessing.  I really want "tracing",
not "profiling".  Statistically, the disk isn't being accessed at all.

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